Paper media bearing permanent ink are non-reusable and are often discarded after being read. Although paper media are relatively inexpensive, the quantity of discarded paper media is enormous and its disposal raises cost and environmental issues.
In contrast to paper media, erasable media may be reused many times to transiently store images and/or text. For example, an erasable medium may include a photochromic material that undergoes reversible photo-induced color change to enable image-writing and image-erasing. Ultraviolet (UV) light is often used to induce image-writing and heat is often used to induce image-erasing.
Examples of erasable media include that described in a commonly assigned U.S. Pat. No. 7,645,560 issued Jan. 12, 2010 and titled “Inkless Reimageable Printing Paper and Method,” the disclosure of which is incorporated in its entirety herein by reference. An embodiment of the erasable medium formulation detailed in the patent includes a photochromic material, for example an alkoxy modified dithienylethene. Use of this material allows for the imaging of a pattern onto the medium using patterned ultraviolet (UV) light. The UV light chemically alters the formulation to produce a visible image pattern. The image remains visible for a period of time, but is erasable on demand using one or more of heat and visible light. The chemical formulation of the erasable medium is re-imageable such that the same or a different pattern can be re-imaged.
There are several different types of conventional pens, including ballpoint, rollerball, fountain, and felt-tip, which are used for writing. The writing is achieved by applying permanent ink to a surface of, for example, paper media. However, conventional ink pens can not be used in the context of the reusable erasable media, due in part to the composition of erasable media and further due to the permanent nature of conventional ink pens. Digital pens have also been introduced that include memory storage for the recording of written and oral notes.
Additionally, pens have been developed specifically for use with erasable media. Example pens designed for use with erasable media include that described in commonly assigned U.S. patent application Ser. No. 12/573,478 filed Oct. 5, 2009 and titled “Pen Specific for Erasable Media Usage,” the disclosure of which is incorporated in its entirety herein by reference. An embodiment of the pen for use with erasable media includes a pen barrel, a first radiant energy source mounted within a writing end of the pen barrel, and a second radiant energy source mounted within an erasing end of the pen barrel. The first radiant energy source is configured to image an erasable medium, while the second radiant energy source is configured to erase an imaged region of the erasable medium.
Pens for use with erasable media, however, do not include any mechanisms for storing handwritten marks in a computer readable format. Conventional digital pens use permanent ink and cannot be used with erasable media. Therefore, there is a need to overcome these and other problems in the prior art and to provide a pen, having certain attributes of a conventional ink digital pen, but specific to imaging and erasing of erasable media.